docs: def edge_node(name, points):
      """
      :param name: 'faultTopEdge', 'intermediateEdge' or 'faultBottomEdge'
      :param points: a list of Point objects
      :returns: a Node of kind faultTopEdge, intermediateEdge or faultBottomEdge
      """
      line = []
      for point in points:
          line.append(point.longitude)
          line.append(point.latitude)
          line.append(point.depth)
      pos = Node('gml:posList', {}, line)
      node = Node(name, nodes=[Node('gml:LineString', nodes=[pos])])
      return node